There are 30 million post-menopausal women in the U.S. today, and the numbers will grow as the baby boomer generation ages. About one-quarter of these women are taking some form of estrogen replacement therapy (ERT). Significant controversies exist about the risks and benefits of ERT, and the large-scale trials, such as the WHI, while of vital importance, will not help women to make decisions in the next few years. It is the trade-offs between cancer risks and heart and related disease benefits that make the decision difficult and immensely personal. Yet, the few studies that have been conducted suggest that women want more information than they are receiving. The goal of this study is to promote informed decision making about ERT. To do that, it is essential to understand how womens knowledge, beliefs and perceptions of risks and benefits influence their decisions about ERT. We also will evaluate the impact of a tailored print intervention on improving decision making. Two complementary studies will be conducted; an Observational Study will be conducted to contribute to answering the first question; and an Intervention Study will be conducted to answer the second. Over 3000 women will be included in these studies, and we have taken a number of steps to assure adequate minority representation. There is sufficient power to answer the major study questions. A cost.effectiveness analysis will determine whether the intervention is one that could be replicated in a cost-effective manner. It is imperative that risk communication strategies that enable women to make informed decisions about ERT be designed, implemented and evaluated. This study represents an important step in that direction.